Atypical interpersonal brain synchronization in children and adolescents with autism in parent-child dyads: a hyperscanning study using fNIRS

Background: Interpersonal brain synchronization has repeatedly been demonstrated during joint social tasks for healthy adults and recently also for parent-child dyads. Pioneering stu-dies have demonstrated diminished brain-to-brain synchrony in adults with autism spectrum disorder (ASD) during such tasks. To date, no study has investigated this in children with ASD and has examined whether the familiarity of the interaction partner modulates interpersonal brain synchronization.Methods: Using functional near-infrared spectroscopy (fNIRS) hyperscanning, we assessed brain-to-brain synchrony during a cooperative and a competitive computer task in 43 typical-ly developing (TD) children and 15 children with ASD (8-18 years) while playing with one of their parents. Adult strangers performed the identical tasks with each child. Participants were instructed to either respond jointly via button press in response to a target (cooperation) or to respond faster than the other player (competition). Within each dyad, wavelet coherence was calculated for corresponding channels as a measure of brain-to-brain synchrony.Results: Preliminary behavioral results showed that the dyad’s cooperative performance was neither influenced by interaction partner nor by group. During competition, the child won more often against the parent than the stranger, and children with ASD won more often against parent/stranger than TD children. On the neural level, preliminary results revealed a significant interaction of partner and group for coherence in two channels located in Brodmann areas 8 and 9: coherence in the ASD group was significantly smaller when playing with the parent compared to a stranger. No significant effect of partner was observed in the TD group.Conclusions: Data collection in both samples is ongoing. Preliminary results suggest differen-tial coherence in ASD with respect to the interaction partner’s familiarity. In a larger sample it remains to be seen, whether fNIRS hyperscanning represents a valuable tool for investigating brain-to-brain synchrony during social tasks as a proxy for typical and atypical social inter-action.gyrus, and (2) the right lateral orbitofrontal cortex and insula. Across all individuals with ASD symptomatology, we observed a significant positive correlation between lGI of cluster 1 and symptom severity in the ADI-R subscale of restricted and repetitive behaviour (r = 0.4, p < 0.05).Conclusions: Our findings imply that even though sharing similar ASD-symptomatology, the patterns of cortical folding differ between individuals with the microdeletion and those without